The Civil Guard Information Service (Spanish: Servicio de Información de la Guardia Civil, SIGC) is an intelligence service within the Spanish Civil Guard responsible for the collection, analysis and distribution of information relevant to domestic security, as well as its exploitation or operational use, especially in matters of counterterrorism, both nationally and internationally.

Likewise, in the 1930s the "Railway Brigades" were created, plainclothes groups in charge of monitoring rail transport and whose components, for the most part, ended up joining the SIGC.

That year, the Civil Guard was completely reorganized by means of the Law of March 15, 1940[5] and the Order of April 8, 1940 that developed it, creating the Civil Guard' General Staff and mentioning for the first time an information service integrated in the Second Section of the General Staff.

[6] To comply with this mandate, on February 24, 1941, the director-general of the Civil Guard issued a circular, completed by the reserved order of April 1, 1941, which contained the precise instructions for putting the service into operation, creating thus, officially, the Civil Guard Information Service (SIGC).

[7][4] During the period of activity of the terrorist group ETA, the SIGC, together with the General Commissariat of Information (CGI), have been the most responsible for its combat and dismantling.